Method of preparing dried egg product



Patented Mar. 20, 1934 UNITED STATES PATENT OFFICE Samuel Tranin, mCity, M0.

N0 Drawing. Application January 15, 1932, Serial N0. 586,970

2 Claims. (01. 99-5) The principal objects'of this invention are toconserve and enhance the natural properties of. raw, normally liquidfoods, and to prevent deterioration of the quality of liquid foods byprocesses of preparing the foods for storage and shipment.

Liquid eggs tend to lose desirable volatile constituents, and aresubject to deterioration by atmospheric air, when prepared by ordinarymeans. Particular objects of this invention, therefore, are to increasethe desirable gaseous content of dried and frozen egg, and to protectthe egg from the unfavorable effects of contact with air before, duringand after the eggs are conditioned for storage or shipment. 4 r

In accomplishing these and other objects of the invention, I havedevised novel steps in the preparation of liquid egg for the market, aspresently disclosed. The novel method may be carried out by employingequipment well known in dehydration, spraying and freezing industries,and which, therefore, need not be described in detail.

In one aspect the invention consists in adding a volatile agent to abody of raw food in the liquid state, and treating the body to retainthe agent, whereby a food may be provided having an increased content ofvolatile substances. This aspect of the invention will first-bedescribed in its application to the treatment of commercial raw, brokenegg to provide a productadapted for use by bakers.

The ordinary liquid egg product of commerce, while wholesome andheretofore considered satisfactory, has been deficient in someproperties, chiefly by lacking the beating quality of freshly brokeneggs. One reason for the deficiency specified is the escape of volatilesubstances, such as carbon dioxide, from the liquid egg between the timeof breaking the eggs in the factory and their use by the baker. When theliquid eggs are frozen for storage and shipment, the loss of carbondioxide may be due to the length of time the broken eggs are exposedtoair before, during and after freezing, whereby a substantial proportionof the volatile substances is allowed to escape. When the liquid egg isdehydrated to provide solid particles of dried egg, the volatilesubstances, including carbon dioxide, are dissipated with the watermoisture in the evaporation chamber.

I have found that a volatile substance harmless in food may be added tothe liquid food to assure the desirable properties in the product whenused by the baker, and that retention of the volatile agent may beassured by the use of novel treating steps in the process ofconditioning the, food for storage or shipment. In preparing an eggproduct, therefore, I add an agent, such as a gas, and preferably a gassuch as carbon dioxide normally present in broken eggs, and treat theeggs for preservation, in such a manner as to conservethe carbon dioxidecontent of the mixture and protect-the egg from contamination.

Preferred steps in the preparation of dried egg will first be describedin detail, to illustrate the use of the invention and indicate theadvantages of the product due to the novel steps of manufacture.

A body of broken egg, consisting of whole egg, whites or yolks, fromwhich fibrous matter has been removed, is thoroughly mixed or cut upwhile excluded from air and thus a homogeneous mass is produced withoutbeating up the egg. A protective substance is mixed with the mass ofegg, preferably during the cutting-up step, to conserve the desirableconstituents of the egg when the mass is sprayed into an oven aspresently de-' scribed.

The protective substance may consist of any one of several classes ofmaterials such as gums, casein, glycerine, salt and sugar which tend toform seals to prevent escape of volatile constituents of egg. I havefound the most useful protective agents are water-soluble substancessuch as sugar, salt and glycerine having the common characteristic thatthey tend to pass quickly from the interior to the surface of large orsmall portions of liquid foods and collect on the surface toformsubstantially continuous coatings.

I have found that sugar and salt give the best protection, by formingcoatings of crystals on egg particles, the salt giving about 60 per centas much protection as sugar, while glycerine gives about 40 per cent theprotection afiorded by sugar. I, therefore, mix about 5 per cent ofsugar with the body of broken egg, preferably dissolving the sugar inthe egg.

The mixture, protected from contact with air, is prepared in ortransferred to an air-tight tank, and a tube having an inlet adjacentthe bottom of the tank is provided with a small outlet nozzle fordelivering the mixture in a thin stream into a drying oven. Suflicientpressure; for example pounds, is maintained on the mixture in the tankto move the mixture through the tube and nozzle at low velocity. Thispressure is preferably maintained by delivering a gas into the top ofthe tank to act on the body of liquid therein. The gas may consist ofair mixed with carbon dioxide, but preferably comprises carbon dioxide,thus avoiding possibility of contact of deleterious gases such asuncleaned atmospheric air with the liquid food, by which the egg mightbe oxidized or contaminated.

The pressure under which the liquid passes from. the tank to the oven isinsumcient to create a spray. In order to atomize the liquid, I providecoaxial nozzles, such as well known in the atomizing, liquid mixing andspraying arts, comprising a nozzle having a small central outlet forliquid, and an annular nozzle surrounding the liquid outlet. I thendischarge a treating gas, heavier than air, at substantial pressure, forexample 60 pounds, through the annular nozzle. The treating gas mayconsist of air mixed with carbon dioxide, but I preferably selectsubstantially pure carbon dioxide as the propelling gas, one reasonbeing that liquid egg normally contains carbon dioxide, and another thatcarbon dioxide when mixed with egg will increase the beating-up qualityof the egg. The carbon dioxide may be supplied from a tank containingthe gas in liquid form, and pass'from the tank to a compressor fordelivery to the nozzles.

The annular current of carbon dioxide discharged around the solid streamof liquid egg performs several functions. The hollow stream of carbondioxide under pressure tends ,to create a vacuum and moving atrelatively high velocity distributes and dissipates the liquid egg,accelerating and breaking up the solid stream and atomizing or sprayingthe liquid egg into the oven.

The conduit for liquid egg may extend upwardly in the egg tank from thebottom and have a laterally directed outlet. The current of carbondioxide may carry the egg particles a substantial distance, for examplespraying the particles across a 20-foot drying chamber.

Air may be passed through the chamber to take up and carry awaymoisture, the air exhausted being mixed with carbon dioxide.

The hollow stream of carbon dioxide also acts as a shield or cover forthe stream of liquid egg, and for the droplets into which the stream ofegg is broken. Among the protective effects of the carbon dioxide arethe insulation of the food stream and particles from atmospheric air andair in the oven, and the retention of volatile constituents of the eggparticles.

The carbon dioxide discharged into the oven also tends to form anatmosphere of carbon dioxide in the oven for drying the egg particles.The process thus obviates possible contamination of egg by air, andcontact and absorption of air by the egg particles which would incurpossible deterioration of the egg. Carbon dioxide mixes with the eggparticles and is incorporated in the particles, thus increasing thecarbon dioxide content of the egg.

When the moisture starts to go out of the egg particles under theinfluence of the heat of the oven, the sugar comes to the surfaces ofthe damage to the egg. Thecoating substance both insulates theheat-susceptible egg constituents and protects the egg from air, and thecarbon dioxide protects the egg from air both by providing a carbondioxide atmosphere and by becoming incorporated with the egg particles.

The particles of dried egg, coated with sugar crystals which retain CO2,are collected and packaged. When water is added the sugar coatingsdissolve immediately. If the mass is beaten up at once, it will have 10to 15 percent b gger When the improved method of preparing a liquid eggproduct is employed for producing frozen egg, the combined streams ofegg and carbon dioxide are discharged into a refrigerating chamber wheresprayed particles will be frozen and fall in a form resembling snow, orto a refrigerated roller. The carbon dioxide propels the egg through thechamber, or to the roller, and mixes with the spray droplets toincorporate the carbon dioxide with the egg. As in the case of atomizingin an oven, each minute particle of egg will then contain added carbondioxide, and

the atmosphere in the refrigerating chamber will consist largely ofcarbon dioxide.

I have found that the retention of carbon dioxide in egg particles ispromoted, and the quality of the product improved, when the rate offreezing is rapid, so that the droplets congeal into crystals quicklyafter entering the chamber, and almost instantly upon being deposited ona roller. When carbon dioxide is mixed with liquid egg, and the mixtureis frozen quickly, an excess of carbon dioxide and absence of air in theegg are assured. The frozen egg, when melted and immediately beaten up,will have a substantially larger volume and produce cake of largervolume than frozen eggs prepared by ordinary methods.

The improved method may be adapted by ordinary skill to the productionof .foods in any type of apparatus. For examplerliquid egg containingadded carbon dioxide may be frozen quickly in a tank in which themixture is produced, or may be delivered to a belt in an evaporatingchamber for producing flaky egg.

It is apparent, therefore, that I have provided useful improvements inmethods of preparing food products and ingredients, whereby desirableproperties are conserved and enhanced, and whereby novel products may beprepared, including raw broken egg uncontaminated and not affectedchemically by air or oxygen, and therefore more wholesome and havingimproved qualities for treatment by users and incorporation in foods.

What I claim and desire to secureby Letters Patent is: v

l. Themethod of treating liquid egg including dissolving sugar in liquidegg to form a liquid egg mixture, spraying the egg mixture withcarbon-dioxide gas to effect atomization of the liquid coating abouteach particle for retention oi the,

absorbed carbon-dioxide gas in the egg particles. 2. The method ofdrying liquid egg including dissolving sugar in liquid egg to form aliquid egg mixture, spraying the egg mixture with carbun-dioxide gas toeffect atomization of the liquid egg and absorption oi carbon-dioxidegas by the atomized egg particles, and applying heat to the 888particles while in a confined body of carbon-dioxide gas to effectformation of a glazed. protective coating about each particle forretention oi the absorbed carbon-dioxide gas in the egg particles,

SAMUEL TRANIN.

